The present invention generally relates to spray washing systems and, more particularly, to container washing apparatus including one or more liquid supply pipes each having a series of aligned fan spray nozzles.
Conventional container washing systems utilize a large quantity of spray nozzles, often several hundred or thousands in number, extending from opposite sides of several supply pipes. The supply pipes are mounted both over and under a liquid permeable conveyor mat formed of an open mesh material, such as plastic or stainless steel, which moves the containers past the spray nozzles. In such container washing systems, the containers may move along a path often stretching over one hundred feet long and past many different washing, rinsing and treating stations of the system. The spray nozzles at washing and rinsing stations are usually of the type that discharge an elongated, narrow "fan" spray. Pressurized fan sprays are very effective for the washing operations. When oriented correctly and precisely, the use of fan sprays results in full, efficient spray coverage and prevents cans from being dislodged or knocked over on the conveyor.
The proper orientation of the spray nozzles is one in which all of the fan sprays discharged from a given supply pipe are aligned in a staggered fashion, but parallel with one another and parallel to the longitudinal axis of the supply pipe. Also, when used in a container washing system having opposed pipes mounted above and below the conveyor with the spray nozzles of each pipe respectively oriented downwardly and upwardly, opposed spray nozzle orifices must be directly aligned with each other. This prevents the opposing fan sprays from dislodging or knocking over the moving containers, especially lightweight aluminum or steel beverage cans. Instead, fan sprays which are directly opposed and aligned with respect to one another will act on the cans in a stabilizing manner.
In the past, spray nozzles have been attached to the supply pipes by straight or elbow fittings threaded directly into the supply pipes. Such fittings generally include two externally threaded portions, one on each the opposite ends thereof. The first end is threaded into a supply pipe, while the other end receives an internally or externally threaded nozzle. The fitting is meant to remain in place once it is connected to a supply pipe. The nozzle, however, needs to be removed and replaced quite often for cleaning and maintenance purposes.
Large amounts of time are spent by maintenance personnel to initially install the large number of fan spray nozzles during set-up of the system and during the removal and attachment all of the spray nozzles periodically for cleaning, maintenance or replacement purposes. This system "down-time" or inactivity is obviously costly and undesirable. Unfortunately, with current systems such as large can washing systems, installation and maintenance is a lengthy, labor intensive process due to the very large number of nozzles. Each nozzle must be threaded onto a supply pipe fitting in a fluid tight manner, while also orienting the fan spray pattern of each nozzle precisely parallel to the central longitudinal axis of the supply pipe and to the oppositely directed nozzle of an opposed supply pipe. This is often very difficult when straight threaded fittings are being used because, as a spray nozzle is being threaded onto the fitting, the threaded fitting many times will turn into the supply pipe. In all applications using threaded nozzles, the inaccurate nature of the threads themselves makes precise alignment very difficult.
The process of aligning all of the spray nozzles in the manner described above has generally been a trial-and-error process. Certain attempts have been made to make the attachment and alignment process easier. For example, system installers or maintenance personnel have placed markings on the spray nozzles and associated fittings to indicate when the nozzle should stop being turned relative to the fitting. Unfortunately, crude markings cannot indicate the rotational position of the nozzle relative to the fitting with the precision necessary to properly align a fan spray pattern. Also, this alignment method relies on the threaded fitting remaining stationary and, in the case of a straight fitting, fails as soon as the fitting turns into the pipe during the attachment of the spray nozzle.
U.S. Pat. No. 2,548,788 discloses a pasteurizing device which utilizes a central supply pipe having a plurality of spray nozzles attached thereto. While these spray nozzles are not threaded directly into the supply pipe, they still include spray nozzle caps threaded onto nipples which, in turn, are threaded into nozzle attachments connected to the supply pipe by laterally extending tubes. This arrangement therefore does not solve the problems mentioned above for the specific application of fan spray nozzles which must be repeatedly attached in precise alignment. Due to the threaded connections of the various nozzle parts disclosed in U.S. Pat. No. 2,548,788, too much "play" or part rotation would be possible during each nozzle attachment procedure. Although integral, one-piece threaded elbow fittings are also known, even these are undesirable due to the inherent imprecision of the threaded nozzle attachment.
It would therefore be desirable to provide a spray system and, more particularly, a container washing apparatus in which a large number of fan spray nozzles may be quickly connected to one or more supply pipes in a fluid-tight manner and with their fan spray patterns in precise parallel alignment with each other and with the longitudinal axis of the supply pipe.